The present invention relates generally to keyboard apparatus and more particularly to calculator keyboard apparatus. The number of different functions performed by a calculator is limited by the number of keyboard configurations available to the user. Each configuration represents a combination of different keys of the keyboard. A key may be used for as many different functions as there are labels or physical marks upon it or near it identifying the key. It is often difficult, however, to establish more than three such marks on or near a key to identify it for multiple use. To significantly increase the number of functions that may be performed by a key, therefore, it is desirable to be able to mark or identify the key with many labels.